This invention relates to a process for the production of kappa-caseino-glycomacropeptide (hereinafter referred to as CGMP).
CGMP is a sialylated macropeptide which is formed by the action of rennet or pepsin on kappa-casein from the milk of mammals.
In one known laboratory process for the preparation of CGMP, a starting material of lactic origin, such as for example an acidic casein or a caseinate hydrolyzed by rennet, or even a demineralized, lactose-free sweet whey, is treated with trichloroacetic acid to precipitate the proteins, the supernatant is collected and dialyzed and, finally, the dialyzate is dried. However, this process is not an industrial process.
According to European Patent Application Publication No. 291 264, CGMP may be produced on an industrial scale by hydrolysis of acidic casein or sodium or calcium caseinate with rennet which leads to the coagulation of para-kappa-casein. The supernatant is then acidified to pH 4 - 5 to precipitate the calcium phosphocaseinate. After separation of the precipitate, the solution is neutralized, demineralized by reverse osmosis and, finally, is concentrated and dried.
According to French Patent Application No. 2,288,477, glycoproteins and sialic acid may be industrially produced from whey emanating from cheese production by flocculation of the whey proteins, recovery of the supernatant and ultrafiltration of the supernatant using membranes having a cutoff threshold of approximately 15,000 dalton which produces a retentate containing the sialo-glycoproteins from which sialic acid is obtained by hydrolysis with sulfuric acid, neutralization with barium hydroxide, separation of the barium sulfate precipitated and isolation of the sialic acids from the supernatant by ion exchange.
None of the industrial processes mentioned above gives a CGMP with the purity desirable for its use as an anti-infectious agent, i.e., containing hardly any proteins, lactose and residual minerals and most of the sialic acids.
The problem addressed by the present invention was to produce CGMP having the qualities mentioned above on an industrial scale.